Sources for rear differentials-- what you get--

[PorchDog]

Freedom of Choice-- is what you get---DEVO

OK, on my manual transmission bus, it had a 4.78, and I wanted to re-gear to a 4.10. All this medium duty stuff is relatively new to me-- so I get on the internet-- and find a bunch of used ones with some guarantee--VanderHaag's has some-- and relatively cheap. I think I bought the first 4.10 for maybe around $500. Freight was relatively cheap, and no core charge. So-- I went ahead with the purchase. The old rear diff whined some, and I did not know exactly what to expect as far as what is normal. I get the used differential from VanderHaag's and install it--using my newly purchased Harbor Freight HD floor transmission jack. The used differential works fine, but whines too.


Then I watch Chuck Cassady's YouTube video where he installs a rear differential from LKQ. It is supposedly inspected, and comes all painted up in primer red. In my mind I think it is rebuilt. Some months have passed since the first install-- I am tired of the whining--so I call LKQ, and buy a differential from them--again thinking this will cure my whine and that this differential would have been rebuilt. I want to think I paid about $1300 or so with no core. I get it, install it, and it whines too-- so I think maybe this is normal.

Now-- move to bus number two-- (and for sure my last one per my wife) and it has a 6.14, and I want to go to 5.38. It is a 19,500 pound rear axle where the first bus was 17,500 pound. I call LKQ, and it takes them a few days to come up with one, and again they tell me about $1300 or so (I can't find my paperwork) and I ask "are these units rebuilt?" Turns out they are inspected and guaranteed, but NOT rebuilt. I asked how much a remanufactured one was-- and seems like the quote was slightly over $2000. Now I realize that my LKQ unit was cleaned up, inspected, and painted-- not reman.

I look further. I call Fleet Pride-- their reman units are $2200 or so. Then they ask me if I have an automatic transmission?-- which I do on this bus-- and they begin telling why I should not change the gear ratio, I would have transmission issues, etc. They really didn't want to sell me a differential.

Back to the internet-- and I find ProGear in Orlando FL. $1350 for a reman unit with a $700 core charge, and freight to me in Alabama was $650 or so-- which I thought was really high. Before I forget -- this bus has over 300,000 miles on the frame, and the rear axle runs fine, does not leak, but it whines.

I know my core is good, pull it out, and me and the wife drive 12 hours to Orlando and get to stay in a hotel, and eat some sea food, and eat at Waffle house, and have a mini vacation. Also negates shipping the core back. I get to see these folks operation, they have over 300 transmissions and rear differentials in stock for medium and heavy duty trucks ready to ship, and the same owners have been there for over 30 years.

We get home, I install the differential-- and guess what-- it does not whine!

My reason for relating this tale of two (or three) rear ends is that it does make a difference if they have actually been disassembled, inspected, and then set back up like they should be. The used one was luck of the draw-- you get what you get-- maybe good maybe not so good-- on the LKQ unit-- the rattle can remanufactured made me think these had been gone through-- but all they did was make sure it didn't have obvious bad bearings or broken teeth, and the real value came when folks who know what they are doing actually remanufactured the unit.


It is so nice to ride in the bus without the whine. My bus is gutted -- and I get a kick out of driving it-- and the last miracle I have discovered in the last few days are Apple Earbuds or whatever you call them. Through the sheer miracle of active noise cancellation-- all the noise in the open concept bus just disappears. We live in an age of miracles...

That's all folks!

[nikitis]

Noise cancellation is something I put on my list after my recent first trip of 1000 miles to Florida. I just bought some ear buds yesterday, and will try to use them. These won't cancel noise quite as good as others, but I should be able to hear.

My rear axle whines too around 45MPH, but once I get to 50, it quiets down. I think it ran for so long speed limited to 45, it wore the gears into bad shape at that speed of 45 MPH. When I hit 55 MPH it completely goes away, and I do not hear it at all. I have a good axle ratio of 4.78. I'm told that's a good ratio for highway speed, I'm just stuck with an AT545, so when I remove my transmission i'll see if i need to go lower after that.

[Omnibot2000]

My first diff. growled. Carrier bearing gone. It also had a whine. Diff was set up so bad that a major shop that rebuild diffs said the crown and pinion was trashed. Was previously worked on

I would have loved to have looked at it, alas it was November and I have a gravel driveway and labor was cheap I said screw it.

My new used diff briefly whines between 80-90kmph or in around there but at cruising speed it's silent. Also helps I am running steer tires on the drives as well.

[cadillackid]

some whine some dont.. my 4.44 i got recently (CHEAP) for my redbyrd whines at about 55 MPH then is really quiet above that... it is used, inspected and readjusted my mchigan truck parts.. (they paste them so you can inspect the gear mesh before you buy)... it was 1/3 the cost of going to weller and having my original unit re-geared with the new gears.. was also within driving distance so it was just gasoline for my pickup, a 3.5 hour drive (got to try out 2 new coffee shops id never hit before). and a cool road trip...



I went back N forth about having one built and getting a different one used... since the price was over $1500 difference i went with the used inspected, re-adjusted and in-spec used.. it does have the whine in the one RPM range... this isnt a lot different than many busses and trucks ive driven with not a lot of miles even.. if I have trouble in the future id probably go with the new / reman unit my typical cruise speed is 65 and my dif is silent there... i do drive 55-60 (MPH) on some back roads so i do hear the whine then some.. my stereo is loud if i want it to be

[Omnibot2000]

I would like to add.

I have reduced or eliminated gear noise by changing to a heavier grade gear oil.

The equipment I currently work on run 75w-90 gear oil. The diffs are stop and go city duty and for the most part run cold.

I also worked for a Freight company that ran highway heavily loaded. They ran 75w-140 gear oil.

My diff when installed was filled with 75w-90 last November. I took it on a trip this summer and heard the gear whine in a tight speed range.

My bus is lightly loaded all considering and anticipated usage will be highway speeds, more heat. I may just go with conventional 80w-140 as for the most part, my rig is just a 3 season toy and the thicker oil may silent the brief whine I have. I'll likely change it out in the spring.

I do have a book with pictures showing normal wear pockets in the crown which is considered normal and still serviceable. I would imagine they can cause a whining sound when the service application changes. I have done a few diffs but not something I would say I specialize in to really know.

The industry now has moved to, fleet mechanic take it out. Send diff. in for repair. Recieved diff. and install. If diff fails, it's warrantied through the shop that rebuilt the diff.

Really, last diff I rebuilt with new crown and pinion was on a Kubota ag. tractor 6 months ago. Lol

[nikitis]

I had this thought about rear diff gear old and using a thicker oil. Though I don't know much about the current weight my oil is. Likely what they put in standard.

I'm curious to know if this works for you as I may do the same. I just had all my rear gear oil changed as I had a leaky pinion seal and replaced the seal.

[Omnibot2000]

Originally Posted by nikitis

I had this thought about rear diff gear old and using a thicker oil. Though I don't know much about the current weight my oil is. Likely what they put in standard.

I'm curious to know if this works for you as I may do the same. I just had all my rear gear oil changed as I had a leaky pinion seal and replaced the seal.

Call the shop and find out what they used? Just a thought.

Some shops will use just one particular oil. Shops try to consolidate and purchase in bulk. Right or wrong it happens.

We use 75w90 because the reason listed. However we also use 5w-40 full syn. engine oil for all diesel engines no mater what it's called for.

Example. PACCAR engine uses 10w30 at my 2nd last job and Detroit dd16 wanted 15w40. I consolidated the the fleet to one oil of 5w40, purchased in bulk. Extended the oil drain intervals while maintaining warranty and getting a price break on the oil. Ended up being a wash for labor and extra parts cost from synthetic oil and reduced labour time with extended drain intervals but I also increased truck up time.

Either way, way off topic

[cadillackid]

if the thicker oil makes a difference wouldnt your diff be much quieter when you first start out in the AM vs later? if the noise is the same then id think you are hearing the gears and not the oil so much..

[Omnibot2000]

Originally Posted by cadillackid

if the thicker oil makes a difference wouldnt your diff be much quieter when you first start out in the AM vs later? if the noise is the same then id think you are hearing the gears and not the oil so much..

True. Running thicker oil is not guaranteed.

I'm not saying and maybe I should clarify this. It's not a guaranteed fix. Maybe my wording was not the best in my other post.

For my personal bus I have pulled onto the highway and has a slight whine, as it heated up the whine become a little more prevalent. Depending on how how loud it is to begin with is key.

Some people are more sensitive to odd noises then others. While some can pin point the faintest of noises, other people seem totally oblivious to a banging noises hammering away under the cab and is shocked that something is wrong..

I suppose I could use this as an example. We had a lady driver at my last job. While driving bus the windows on the bus would rattle a little. She was stuffing paper in all the window slides to stop the rattling. As per her, it would give her migraines after a 3 hr bus run. I also had to replace her driver seat because it had a squeak that we could not resolve.

[cadillackid]

Originally Posted by Omnibot2000

True. Running thicker oil is not guaranteed.

I'm not saying and maybe I should clarify this. It's not a guaranteed fix. Maybe my wording was not the best in my other post.

For my personal bus I have pulled onto the highway and has a slight whine, as it heated up the whine become a little more prevalent. Depending on how how loud it is to begin with is key.

Some people are more sensitive to odd noises then others. While some can pin point the faintest of noises, other people seem totally oblivious to a banging noises hammering away under the cab and is shocked that something is wrong..

I suppose I could use this as an example. We had a lady driver at my last job. While driving bus the windows on the bus would rattle a little. She was stuffing paper in all the window slides to stop the rattling. As per her, it would give her migraines after a 3 hr bus run. I also had to replace her driver seat because it had a squeak that we could not resolve.

whats interesting is im that way about my cars.. esp my new ones.. my hyundai developed a very minor "rattle" that would drive me crazy.. turns out it was the little metal key ring on a garage door clicker rattling as it sat in the front tray by the dash.. i took the ring of and all is good..


i can drive my busses with squeaks and rattles and kuwangs over sewer drains and not think a thing. mechanical sounds that are rhythmic from say the engine or the wheels or vibrations etc will though grab my attention every time...

[Booyah45828]

Originally Posted by Omnibot2000

However we also use 5w-40 full syn. engine oil for all diesel engines no mater what it's called for.

Example. PACCAR engine uses 10w30 at my 2nd last job and Detroit dd16 wanted 15w40. I consolidated the the fleet to one oil of 5w40, purchased in bulk. Extended the oil drain intervals while maintaining warranty and getting a price break on the oil. Ended up being a wash for labor and extra parts cost from synthetic oil and reduced labour time with extended drain intervals but I also increased truck up time.

Either way, way off topic

We switched to that a few years ago. At our costs a good synthetic 5w40 is only a few bucks more then a good conventional 15w40 per gallon. Start-ability in the winter is much better with the 5w40 and with testing I've found the 5w40 viscosity remains stable for longer.

All pros no cons in my book.

[Booyah45828]

Porchdog, Sorry you had to find the dirty details of the "reman" market the hard way.

There are too many places that consider a reman to be a visual inspection coupled with a fresh coat of paint.

FWIW my bus whined too. I considered it normal on an old bus with mileage. Nothing crazy though as you could only hear it if you were sitting in the back though. Sitting in the middle or up front you heard the engine, or the trans if it wasn't in 4th(at545).

We go with weller for all of the reman stuff we use in the shop. They're top notch and we've had no issues. I'm glad you found a place that made you happy. Keep clean/fresh fluid in it and it should last forever.

[Omnibot2000]

Originally Posted by Booyah45828

We switched to that a few years ago. At our costs a good synthetic 5w40 is only a few bucks more then a good conventional 15w40 per gallon. Start-ability in the winter is much better with the 5w40 and with testing I've found the 5w40 viscosity remains stable for longer.

All pros no cons in my book.

Agreed. Synthetic is way superior.

While the DD16 cranked over better in the cold. I did not notice as much on the paccars running the 10-30 semi synthetic.

Regardless, could not go wrong with the synthetic. We had a loader with 1200 hrs on the syn. oil. User group failed to bring it in. CASE lists 500hr intervals. We sampled the 1200 hr oil with CAT SOS. Oil sample came back healthy. All in the green.

Means alot.

[Mekanic]

I bought a $300 used gear set and reheated mine my self.
If you can set up a 9inch ford axle (one of the simplest car axles) you can do one of the big ones.
You WILL need some larger tools.
I did weld a piece of steel angle to the head on my engine stand to make it easier to work on.

[cadillackid]

Originally Posted by Mekanic

I bought a $300 used gear set and reheated mine my self.
If you can set up a 9inch ford axle (one of the simplest car axles) you can do one of the big ones.
You WILL need some larger tools.
I did weld a piece of steel angle to the head on my engine stand to make it easier to work on.

love working on the 3rd member stuff.. esp the dana / spicer stuff where you dont need shims on the carrier to adjust it side to side.. and no freakin GM C-clips

[Omnibot2000]

Just as a reminder.

These larger diffs usually have higher milage with larger loads.

The wear patter can get funky.

I know I have a book somewhere that talks in some detail about pocket wear but can't find the darn thing right now.

When I was an apprentice back in 1999 or 2000. A much more wiser mechanic then me mention something about painting the Pinion lightly if possible and allow the paint to transfer to the crown to expose the pocket so you can see what your dealing with. If you lather up a used ring it smears the paint and cannot see the pocket as well. He got all the diffs in my learning years and I couldn't tell you if he was full of it . I wish I could have worked along side him. They focussed more on production instead of mentoring.

Anyway, here is what I found after a quick search that briefly talks about it.

Just mentioning this if someone out there wants to take a stab at setting up a diff for the first time.

[Tin Roadtube Vagrant]

I performed rebuilds for Eaton and Mack transmission/diffs at the dealership. Back when we fixed stuff because the reman market wasn't as competitive. The sound of a used gear is related most often to its tooth polish. Not to say engagement doesn't matter..... but a gear with the oil hatching polished off to a mirror finish will ALWAYS whine, even though it's fit for service. The rule was to replace transmission main shaft gears in the top hole position. That's the one the driver will be sitting in the most, will polish the worst, and costs the least because it will be a tiny gear for overdrive or direct. Diffs are no different. If you buy a rebuild.... be aware...... polished gears ARE service worth, but will whine. A new ring and pinion, set up right, is the only guarantee for resonance issues.

[nikitis]

Originally Posted by Omnibot2000

Agreed. Synthetic is way superior.

While the DD16 cranked over better in the cold. I did not notice as much on the paccars running the 10-30 semi synthetic.

Regardless, could not go wrong with the synthetic. We had a loader with 1200 hrs on the syn. oil. User group failed to bring it in. CASE lists 500hr intervals. We sampled the 1200 hr oil with CAT SOS. Oil sample came back healthy. All in the green.

Means alot.

I was always told oil used in diesel engines was always black. When I bought my 3 cylinder diesel mini-excavator that was the case. I'd even change it and couldn't get it to not be black when sampling from dipstick, but I know it was emptied. Mixing in with sidewall sludge I guess.

On my 3Box, The old oil was clear and light brown/yellowish like it was new. No hint of blackness to it. I changed it out anyway because the previous owner said they didn't change it recently and that it was old and I should change it out after driving it home. I can't get the oil to be black in the T444E if I wanted it to be.

[cadillackid]

Great info. The set I got for mine which whines only in a certain narrow range definitely was polished a bit. The gears still look great and the mesh / preload / lash are good but definitely on the shiny side, I never realized that affected whine

[Omnibot2000]

Originally Posted by nikitis

I was always told oil used in diesel engines was always black. When I bought my 3 cylinder diesel mini-excavator that was the case. I'd even change it and couldn't get it to not be black when sampling from dipstick, but I know it was emptied. Mixing in with sidewall sludge I guess.

On my 3Box, The old oil was clear and light brown/yellowish like it was new. No hint of blackness to it. I changed it out anyway because the previous owner said they didn't change it recently and that it was old and I should change it out after driving it home. I can't get the oil to be black in the T444E if I wanted it to be.

Detroit 60 series engine turns oil instant black and disgusting to wash off.

My OBS Ford is changed every 5000kms....so 3000 miles if not sooner. I only use it when needed for towing. Oil does not turn black.

Looks like the old Ford though will be used a bit for a couple weeks.

Hit a deer/buck yesterday morning. Punched a hole through my windshield on the driver side of my commuter car. Kinda out a car for a little bit.